1. FIELD OF THE INVENTION
The present invention relates to an assembly for making oriented bore holes.
One of the objectives of the assembly of the present invention is to allow drains to be formed from existing or drilled vertical wells which are horizontal or inclined with precisely controlled orientation and which are connected to the vertical well by a section having a small radius of curvature (20 to 30 meter).
2. DESCRIPTION OF THE PRIOR ART
The above objective cannot be obtained by any existing system, whether operational or experimental. The conventional horizontal bore hole using conventional drilling pipes involves transitional profiles from the vertical section to the horizontal section which are developed over several hundreds of meters. The drill hole with small radius of curvature using thick articulated drilling pipes does not allow the orientation of the horizontal drain to be controlled efficiently and with precision.
U.S. Pat. Nos. 2,198,016 and 1,850,403 as well as Belgian patent No. BE-A-865,955 and German patent No. DE-A-3,306,405 in addition to an article entitled "Recent developements in forage teleguide", "Revue del'Institut Francais du Petrole", Vol. 38, No. 1, January-February 1983, pages 63-81 provide examples of prior art proposals.
The present invention may be preferably used for forming horizontal drains in shallow oil reservoirs where the horizontal bore is technically or economically inapplicable due to, for example, numerous heavy oil deposits and bituminous sands, or for reactivating old existing oil wells which are no longer productive because of encroachment of, for example, water or gas or due to relative exhaustion. The advantage of this application, with respect to the current solution of boring intermediate vertical wells, increases the depth of the deposits.
It is also possible to utilize the present invention for constructing horizontal drains in the central zone directly below off-shore production drilling where access is not possible, as well as for increasing the rate of working deposits with multiple superimposed horizons by successively working the different horizons through horizontal drains drilled from a single vertical well.
Additionally, the present invention may be utilized for constructing drains following the sinuosities of mineral veins, which are thin and substantially horizontal in, for example, situ lixiviation or situ coal distillation.
The present invention also allows multiple drains to be bored in several directions from a common vertical access well.